Luca Guala: driverless buses will be more transformative than driverless taxis

Part 2 of my letter from Luca Guala, of the Italian consulting firm Mobility Thinklab. (Part 1, on personal rapid transit, is here.)

Last summer, we tested driverless minibuses along a route of 1.3 km on a pedestrianized boulevard in Oristano, a small town in Italy. The idea was to test driverless vehicles mixed with traffic.

Why minibuses and not taxis? Firstly, because it is much simpler to teach a robot to follow a fixed route, rather than teach it to go anywhere the passengers want to go. Such a system is already operational in Rotterdam (2getthere.eu/projects/rivium/) and it works well, but it has one drawback: the tracks are segregated and they represent an ugly severance in the urban tissue.

But if the vehicles are allowed to run with cars cyclists and pedestrians, a public transport route can be “adapted” with unobtrusive measures to accept driverless vehicles, and the people sharing the road will quickly learn to live with them. The main problem here was not technical, as legal.

Hence the idea of testing similar vehicles in an open field mixed with pedestrians. The first test we did had mixed results, the second test that will be done in La Rochelle, France this winter will take advantage of all that we learned in Oristano.

So what did I learn from all of this? That driverless cars very likely have a bright future, but cars they will always be. They may be able to go and park themselves out of harm’s way, they may be able to do more trips per day, but they will still need a 10 ft wide lane to move a flow of 3600 persons per hour. In fact, the advantage of robotic drivers in an extra-urban setting may be very interesting, but their advantages completely fade away in an urban street, where the frequent obstacles and interruptions will make robots provide a performance that will be equal, or worse than, that of a human driver, at least in terms of capacity and density.

True, they will be safer (especially because the liability for accidents will be borne upon the builder) and a robotic traffic will be less prone to congestion (I envision robotic cars marching orderly like robots, packed at 1.5 second intervals, while their occupants fume wishing they could take the wheel perfectly aware, but not at all convinced that their robocars are more efficient drivers than they are – or worse, they DO take the wheel overriding the … robots!), but I do not expect driverless cars to dramatically increase the capacity of a lane to transport persons.

Driverless buses, on the other hand offer an interesting feature: the human driver is no longer needed, removing an important cost and several constraints. This allows them to serve efficiently and economically low-demand routes and time bands, while allowing [agencies] to concentrate the number of manned buses on high demand routes at little added cost.

I take all this automation talk with a grain of salt still, as I don't think we've begun to explore the human response to it. But Luca is right about the key point: driverless buses are a much easier problem than driverless cars, and their space-efficiency will continue to be crucial in busy corridors where even driverless cars will add up to gridlock.

Luca's last paragraph suggests that driverless buses will start with smaller vehicles in simpler situations, which is a possibility. But of course, once the concept is proven, the economics of driverlessness will create pressure to bring the technology to big buses. The same logic is also driving the movement to run fully-grade-separated without drivers, on the model of Vancouver, Dubai, and Paris. The logic of driverless trains is easy: with automated train controls systems there is really not much for a driver to do in non-emergency situations, and these cities have found that those tasks are easily automated. We are all used to small systems of this type, because we encounter them in large airports. The driverless bus in traffic is a harder problem, but we will have solved all of those problems if we ever develop driverless cars. In fact, the problem of the driverless bus, which never goes into alleys or minor streets, should be considerably easier, since navigation turns out to be one of the biggest challenges for the driverless car.

Note also that the challenge of planning for driverless cars is not in envisioning a utopia where they have complete dominion over the street. The future must be evolved, which means that we must plan for the interim state in which some cares are driverless and most aren't. That is a situation where driverless buses could thrive, because they will be competing with something that — in terms of poor capacity utilization — resembles today's traffic on major streets, not a world optimized for the driverless car.

As Luca indicates, we know what the problem with driverless transit will be: long fights with labor unions who feel entitled to cradle-to-grave security in a single job. It will be one more kind of automation that requires people to retrain and to participate in a more complex and competitive economy. In an ideal system, many drivers would be replaced by support jobs such as fare inspectors and roving problem-solvers; as on Vancouver's SkyTrain. This seems to be what Luca is envisioning when he speaks of the continued need for "manned" services.

But the real result of massively abundant transit — which is the real point of the large driverless bus – will be massively more opportunity for all kinds of innovation and commerce to happen in a city, unconstrained by the limits of car-based congestion. That's a wrenching change, and I am as adamant as anyone about the need to protect workers from exploitation. But in the long run, over a generation or two, the outcome will more interesting jobs for everyone. Bus drivers shouldn't encourage their children to go into the same profession with the same expectations, but that's true of many jobs — perhaps even most jobs — in this rapidly changing world.

Why is it that running driverless trains on pre-existing lines requires hundreds of millions of dollars and years of disruptive construction to install “communication-based train control” systems, pushing the prospect of driverless train operation in NYC and London into the 2030s or later, while driverless buses can apparently run on existing streets today?

This is a great conversation, but I want to approach it from a different perspective: what kinds of streets do we want to live on? Do we want cars platooning more closely to improve throughput, or is it more important to be able to cross easily to get from store to store, or to make eye contact with drivers to be sure we know it’s safe to gone in front of them? Cars and highways were the disruptive technologies of my youth, and a generation of planners has spent our full careers attending to their domination of the streetscape. Same as today, technology created real value (allowing people to go and live where they want and when) and also unanticipated side effects. My bias now is to focus on anticipating the side effects, and remember that transportation serves communities, not the other way around. Privately owned automated cars seem fraught with potential to dominate communities even more than today. Drivers will have every incentive to send them home to avoid parking at work or have them drive endlessly around the block rather than to park at a department store. Pedestrians will figure out how to make them stop, but still it will be creepy having ones life depend on a robot stopping and waiting for you to cross safely. But is there a way to thread the needle and have safer, more frequent and reliable transit while making people more central to how we use and design urban streets?

You do have a good point that, legal and political issues aside, the technical challenges of a driverless bus are, in some ways, easier than a driverless car. Google’s driverless cars currently depend on a vast database painstakingly compiled by humans describing all the minute characteristics on the streets they drive on – something that would be far easier to construct for a bus that travels the same every route every day than for a car which could potentially be asked to drive anywhere. (Presumably, humans could still be hired to drive such buses during temporary reroutes due to construction, etc.). However, in spite of this, the reality that public transit agencies tend to be beholden to their drivers’ unions and very risk averse. They won’t want to touch any driverless bus technology until cars and trucks have been using it for decades. The first driverless buses to hit the roads will probably not be public transit buses, but shuttle buses managed by the private sector. I can see airport shuttles to parking lots and rental car facilities being prime candidates for early adopters because their routes are short, have minimal exposure to pedestrians, and operate huge numbers of trips every day.

It depends. When a city needs the jobs more than it needs the money (that would presumably be freed up when drivers arent needed) its not the best idea to implement driver-free bus technology. I know in LA where I live we certainly need those jobs. Transit agencies should focus their efforts on putting in bus-only lanes, something that actually improves the passenger experience, instead of buying expensive technlogy such as this. That said, are they able to develop driverless buses bigger than the ones pictured above? Those look pretty small.

It won’t be busses that do this first….it will be freight…short haul repetitive freight…around airports and ports – to ikea, walmart, Costco…it is the same situation as a bus, but it will be with no people involved at all (way less risk). The initial routes will likely be completely grade separated with short forays across or into traffic – mostly low traffic industrial areas…and will not rely solely on the onboard equipment – but also include sensors mounted along the route (at intersections and in locations where they can minimize risk – for example blind corners). They will then expand to rural areas that require large amounts of supplies trucked in along a single route – think Arizona, or Northern Ontario. Bus automation will happen first on the BRT and small cities who have simpler traffic and budget constraints.

Vancouver’s trains are already driverless and hugely successful. They have a totally grade-separated environment. There’s nothing more to demonstrate in exclusive rights of way; the debate now is over driverless vehicles in less exclusive environments, including outside our front doors.

The automatic driving of a bus may be easy, but what about the interaction with passengers? How does a driverless bus tell the difference between an intending passenger and any other pedestrian; or line up the bus for level boarding if there isn’t sufficient kerb space; or know when to kneel; or realise that something potentially lethal but hard to detect, like a scarf, is caught in the doors? Full BRT-stops will help with this – but think of the cost of providing these sorts of facilities at every single stop on a driverless route.

About drivers unions opposing driverless vehicles: this is indeed a potentially difficult issue. However, in the CityMobil2 demonstrator we did in Oristano last summer, one of the partners was the local bus operator, which lended drivers to act as “on board supervisors” as required by the Italian DoT for this test (we are not ready for full automation yet). The supervisors were instructed beforehand, and the instruction also included a talk about the effect of driverless vehicles on occupation. Our argument was that by implementing driverless technology, the PT operators could deliver a better service with the same resources, increasing the efficiency without the need to reduce personnel. The supervisors, some of which were also union members, were not hostile to this experiment and generally agreed with our considerations. Their contribution to the demostrator was invaluable. Tomorrow morning early I will leave for Lausanne, Switzerland, to discuss the next demonstrators of the CityMobil2 experiment. Among other things, I will propose exploiting cycling infrastructures for automated transport. These vehicles, in the current state of the art, do not mix well with motor-cars but we found they cope well with cyclists. Exploiting cycle infrastructures with other means of transport may provide a good reason to invest in high-quality infrastructures, that are generally questioned because of the little number of cyclists that will benefit from them.

The mini (maybe midi) bus application makes sense insofar, as the relative cost of the driver is highest in smaller vehicles than in bigger ones (compare the crew to passenger ratio between a minibus and a 25m double articulated).

What about security? Half the driver’s job seems to be enforcing fares, kicking rowdy passengers off the bus, and sometimes dealing with worse problems. The idea of a driverless bus seems much less useful than a driverless car. A driverless car allows me to “drive” myself somewhere while I read and write, talk on the phone, have sex with mygf, etc. A driverless bus is just a bus — except you’ve fired the driver! So the bus is now a “dumb” bus that will just breakdown or freeze when faced with complex problems. Sounds like a nightmare.

Mike: As far as hailing the bus goes, there are already some places in Sweden where you do this by pressing a button to activate a flashing light over the bus stop (so that the driver can see you in the dark). It wouldn’t be a far cry to link the buttons directly to the stopping routines of an automated bus. After all, this is basically how elevators already work.

The fact that Vancouver’s driverless trains have been running for almost 30 years points to the relative simplicity of automating a fully-grade-separated railway. The trains do not have to watch for pedestrians or other vehicles, so the automation is simple in comparison to automating vehicles moving on city streets with random mixed traffic. While Vancouver’s system has proven to be very safe and very reliable, it is also very expensive to build. This limits the size of the network and requires bus fleets to move people to and from the train stations. Once street-level automation of buses proves safe, those buses could become a valuable addition to Vancouver’s transit network. Smaller, more frequent automated buses could be a needed improvement to the network as they would spread out passenger arrival at the train stations, eliminating the “pulse” of arriving passengers that fills some trains while leaving others relatively empty.

Driverless buses will actually lead to smaller buses, not large ones, because it permits much higher frequency, and thus greater ridership. I suspect that the economies of scale will make driverless LRT more efficient than driverless large buses.

Hannah- so basically the bus as we know it will cease to exist, and public transit will consist of rail and “buses” of the kind pictured above? The beginning of a new era I suppose. It will be interesting to see how these more compact, van-like vehicles will affect public perception of “the bus” and public transportation in general.

Every other week there is a story in the MSM as to how another big corporation got hacked despite its best efforts to protect its data. I shudder to think what determined terrorists / hackers could do if a sizable chunk of the cars / buses on the street are controlled by computers …

I agree with Ben, it seems like a driverless bus would have lots of security issues. On driverless trains there are usually enough people aboard at any time as a deterrent, and it’s still reasonably easy for fare inspectors to patrol. On the other hand, if buses became driverless but kept the employee to provide security, cleaning, and information, it would be a much more pleasant experience. Maybe they could even sell snacks and drinks to bring in revenue.

Driverless trains are less easy than you think. In London, we have some tube lines that are automatic in the core sections in the peak, but they still need a driver, not least because changing the service pattern when there is disruption (like, every day) turns out to be problematic. The DLR is driverless (well, sort of – there are staff on the trains and they can drive them if required) but it’s much, much simpler and much less of a big deal in terms of capacity than the Tube. Similarly, Paris has precisely one driverless line, 14, which is by far the simplest and shortest. This is no accident. If driverless trains are hard, buses will be much harder, not being grade-separated or having a signalling system to keep them apart.

@Alex: drivers actually make it much harder to change service patterns, because you have to make sure they get their lunch breaks, and that afterward the driver is in the right place to pick up a train, and that the driver finishes their shift at the same place where they started, and so on. Plus, I bet drivers don’t want to spend hours sitting in a siding in a tunnel just in case a gap train is needed. It’s much easier to just keep an automated train parked in a siding somewhere and send it out if some service disruption happens and a gap train is needed. As for Paris, they’ve converted Line 1 to driverless a couple years ago, and they’re slowly proceeding with converting other lines, in particular Line 4. Most of the work and expense is in installing platform screen doors, which are not considered universally necessary for driverless trains (for example, in Vancouver, or on the aforementioned DLR).

The Author

Since 1991 I've been a consulting transit planner, helping to design transit networks and policies for a huge range of communities. My goal here is to start conversations about how transit works, and how we can use it to create better cities and towns. Read more.